The present disclosure relates to an image forming apparatus including an static eliminating device eliminating a static charge remained on a surface of a photosensitive drum and a separating claw separating a recording sheet with a transferred toner from the photosensitive drum, and moreover, relates a supporting member and a cleaning device.
In a general manner of forming an image, a surface of a photosensitive drum is electrically charged to a predetermined electrical potential by a charging device and an electrostatic latent image according to image data is formed on the surface by photographic exposure. The electrostatic latent image is developed with a toner (a developer) by a development device, and then, transferred on a recording sheet by a transferring device. The toner remained on the surface of the photosensitive drum is removed by a cleaning device and a static charge remained on the photosensitive drum is eliminated by a static eliminating device. In the photosensitive drum, a cycle having such electrical charging, photographic exposure and static elimination is repeated in the image forming.
In the transferring device, voltage with an opposite polarity to the toner is applied onto an opposite face to a face having the transferred toner in the recording sheet and the toner is transferred onto the recording sheet from the photosensitive drum. At this time, if the recording sheet is electrically charged, the recording sheet may stay electrostatically attracted onto the photosensitive drum and, therefore, a paper jam may be easily caused. The paper jam is easily caused, particularly, in a case of using many thin recording sheets or in a case of using a recording sheet being easy to electrically charge. In response, there is an image forming apparatus including a separating claw coming into contact with the photosensitive drum in a counter direction to a rotating direction of the photosensitive drum. The separating claw forcedly separates a leading edge of the recording sheet from the photosensitive drum.
Further, the image forming apparatus may include a conveyance auxiliary member at a downstream side from the separating claw in a conveying direction of the recording sheet. The conveyance auxiliary member is configured to guide the recording sheet so as to prevent flotation of recording sheet after separated by the separating claw and contact of an unfixed toner with components and others in the periphery of a conveying path of the recording sheet.
However, because attachment of the separating claw and conveyance auxiliary member causes significant cost increase, it is desirable that the separating claw and conveyance auxiliary member are configured attachable/detachable in accordance with use environment.
Meanwhile, miniaturization of the photosensitive drum according to space saving and acceleration of the image forming apparatus are progressed, and accordingly, a time from the static elimination of the photosensitive drum to the electrical charging in a next cycle is shortened. Therefore, it is necessary to consider an exposure memory of the photosensitive drum. The exposure memory is a phenomenon in which, between an exposed area and an unexposed area in the photosensitive drum after the static elimination, surface electrical potentials are different from each other, and then, the surface of photosensitive drum is electrically charged unevenly in the electrical charging in the next cycle. A problem of the exposure memory is feared particularly in an amorphous silicon photoreceptor.
As a countermeasure to this problem, it is necessary to provide an interval between the static eliminating device and charging device as wider as possible and to secure a time sufficiently attenuating the surface electrical potential of the photosensitive drum before the electrical charging in the next cycle. Therefore, it is necessary to position the static eliminating device at an upstream side from the cleaning device in the rotating direction of the photosensitive drum.
Therefore, the separating claw and conveyance auxiliary member and the static eliminating device are arranged between the transferring device and cleaning device. If the photosensitive drum is miniaturized, because the space between the transferring device and cleaning device becomes narrower, the separating claw and conveyance auxiliary member and the static eliminating device must be arranged in this narrow space.
As a countermeasure to such a problem, it is considered that a space as an optical path of the static elimination light between the static eliminating device and photosensitive drum is used for arranging the separating claw and conveyance auxiliary member. However, because the separating claw and conveyance auxiliary member or a member supporting the separating claw and conveyance auxiliary member obstruct the static elimination light, a light obstruction area where is not irradiated with the static elimination light is formed on the photosensitive drum.